Dry Systems are to be used only in non-conditioned areas of the facility that may be exposed to below freezing temperatures.
Automatic sprinklers are attached to piping containing compressed air. Opening of sprinklers releases compressed air and permits water pressure to open the dry-pipe valve. Water then flows into piping and discharges from opened sprinklers.
Materials
All piping 2” and small to be black or galvanized iron pipe with threaded fittings and joints. Piping of 2-½” and larger to be the same, or with grooved end couplings and joints.
Distribution
As dry type systems are typically installed in back-of-house spaces, routing should be done to minimizes pressure loss in the system and conserve piping.
Sprinklers
All sprinklers are to be UL listed or FM approved with a 175 psig minimum pressure rating. All heat responsive elements to comply with UL 199. Sprinkler type to be determined based on space use and Code requirements. Wire cage guards should be identified by zone where required.
Zoning
All connected areas requiring a dry type system shall be zones together.
Zone Valving
Zone valving for dry type systems are to include a dry pipe valve with all trim and accessories. Dry Type Valves are to be UL 260 compliant with a UL 1486 quick opening device. trim set for air supply, drain, alarm connections, drip valve, pressure gauge, priming chamber and fill line attachment.
Equipment
Air compressor shall be UL 753 compliant. Unit should be fractional horsepower at 120v, single phase.
Draining
Each zone shall have the ability to be drained from its lowest points for maintenance and testing. Drains are to be routed to an open site drain which runs through a separator prior to discharge to the sanitary system.
Inspector’s Test Connection
Install in sprinkler system piping at hydraulically most remote location of each system or zone, complete with shutoff valve, sized and located according to NFPA 13 and Chicago Building Code.